1. Field of the Invention
This invention is in the field of material handling apparatus. The materials handled are segments of film strips, which segments may have attached to them integrated circuit (IC) chips with an IC chip being bonded to a flexible beam lead frame formed on each segment. The handling apparatus consists of rectangular laminar fixtures each with the capability of having one segment removably mounted on it and at least one magazine for such fixtures. The fixtures and magazines are provided with asymmetrically positioned recesses and protrusions so that only a fixture having a predetermined orientation can be stored in a magazine. Once a fixture is stored in a magazine the co-operating protrusions and recesses prevent fixtures in the magazine from changing their orientation relative to the magazine irrespective of the orientation or manner of handling of the magazine.
2. Description of the Prior Art
The development of integrated circuit (IC) chips particularly medium and large scale IC chips has created a need for improved manufacturing processes which lend themselves to automating the connecting of conductive flexible leads of a lead frame to an IC chip and of such chips and a part of their lead frames to substrates or into packages so that the IC chips can be connected into useful electronic circuits. In implementing such provisions, fixtures such as those described and illustrated in U.S. Pat. No. 4,069,496 which issued on Jan. 17, 1978 can be used to removably hold a segment of a film strip on which such an IC chip has been bonded to a lead frame which frame is in turn attached to the segment.
In automating the process of manufacturing hybrid substrates, it is desirable to assemble, or collect, a plurality of fixtures into a magazine such as that described and illustrated in U.S. Pat. No. 4,043,485 which issued on Aug. 23, 1977. Each of the fixtures stored in a magazine may have an IC chip bonded to the segment of film held by each fixture. Each such magazine has the capability of having such fixtures inserted into the magazine by a machine and subsequently removed by a machine as steps in the process of manufacturing electrical circuits. Such circuits are characterized by having a high density of active electrical elements per unit area of the substrate on which the IC chips are mounted. As a result, such substrates are particularly suitable for use in computers and electronic devices of like complexity.
One problem with the prior art fixtures is that if the polarity keys of a stack of such fixtures are aligned, there are two possible orientations of the fixtures in the stack; one in which the surface of the chip to which the lead frame is bonded is up and the other in which that surface is down.
Another problem with the prior art fixtures and magazines is that the fixtures stored in a magazine can have their orientation with respect to the magazine changed if the magazine is placed in a horizontal or inverted position either accidentally or deliberately, particularly if the magazine is not full, when it is laid, or falls down. As a result, some of the fixtures stored, or stacked, in a magazine which had the same initial orientation with respect to the magazine, may be inverted without anyone becoming aware that this has occurred. In any automated process it is obviously important that the possibility, or opportunity, for deviation from the desired arrangement, or orientation of the fixtures stored in a magazine be eliminated to make the manufacturing process more reliable and cost effective.